Infusion set

ABSTRACT

An infusion set comprises a base member ( 60 ), an introducer cap ( 64 ), and an infusion cap ( 54 ). The base member ( 60 ) preferably comprises a soft cannula ( 52 ) extending from a lower side ( 118 ) of the base member ( 60 ), and a port ( 62 ) on an upper side ( 92 ) thereof. The port ( 62 ) is configured to be in fluid communication with the cannula ( 52 ). The port ( 62 ) also comprises a septum ( 130 ) adapted to seal the port ( 62 ) against unwanted fluid flow. The introducer cap ( 64 ) is adapted to be mounted to the base member ( 60 ) and has a needle ( 66 ) adapted to extend through the septum ( 130 ) and said soft cannula ( 52 ) in an assembled position. The infusion cap ( 54 ) comprises a lumen ( 160 ) adapted to receive an elongate flexible tube ( 162 ). The infusion cap ( 54 ) also comprises a hard cannula ( 170 ) adapted to be inserted through the septum ( 130 ) and to place said soft cannula ( 52 ) in fluid communication with said lumen ( 160 ).

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/418,494, filed May 3, 2006, now U.S. Pat. No. 7,407,491, which is acontinuation of U.S. patent application Ser. No. 10/715,985, filed Nov.18, 2003, now U.S. Pat. No. 7,309,326, all of which are herebyincorporated in their entireties by reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates in general to the field of infusion sets and moreparticularly to infusion sets with removable injection needles.

2. Description of the Related Art

Subcutaneous injection is a standard method for the delivery ofmedication into a patient's body. To facilitate frequent or continuoussubcutaneous injection of medication, subcutaneous injection ports areoften used. Such injection ports extend through the skin and may remainin place for several days. Currently, a major application of suchinjection ports is to provide continuous delivery of medication, such asinsulin, from portable pumps carried with the patient. When used with aportable pump, the injection port is typically connected to the pump viaa fluid line. Another application of subcutaneous injection ports is topermit multiple injections of medication into a patient without the needto repuncture the patient's skin. In this application, medication isinjected from a standard medical implement, such as a syringe, through asoft elastomer septum into the injection port which delivers themedication subcutaneously.

Subcutaneous injection ports generally require a sharp, rigid needle topierce the patient's skin when initially attached to the patient.However, if the needle were left in place through the skin to providemedication delivery, after one or two days the needle would becomeuncomfortable to the patient. To solve this problem, infusion sets withremovable needles and soft plastic cannula to be placed inside the bodyof a patient have been developed. However, these sets have manydisadvantages. There remains a need for an improved infusion set that isless bulky, less susceptible to contamination, more comfortable to auser, and easier to use.

SUMMARY

One embodiment of the present invention provides an infusion setcomprising a base member, an introducer cap, and an infusion cap. Thebase member preferably comprises and a port on a first side thereof, anda soft cannula extending from a second side of the base member. The portis configured to be in fluid communication with the cannula. The portalso comprises a septum adapted to seal the port against unwanted fluidflow. The introducer cap is adapted to be mounted to the base member andhas a needle adapted to extend through the septum and said soft cannulain an assembled position. The infusion cap comprises a lumen adapted toreceive an elongate flexible tube. The infusion cap also comprises ahard cannula adapted to be inserted through the septum and to place saidsoft cannula in fluid communication with said lumen.

The base member is preferably circular, and the port preferablycomprises a cylindrical portion extending from a first side of the basemember. The introducer cap preferably comprises a hollow cylindricalportion extending from the second side of the introducer cap and locatedcoaxially with the introducer needle. The infusion cap preferablycomprises a hollow cylindrical portion extending from the second side ofthe infusion cap and located coaxially with the hard cannula. The firstside of the infusion cap preferably is dome-shaped, and the infusion capis preferably adapted to be rotatable relative to the base member whenthe infusion cap and the base member are assembled.

The base is preferably surrounded by a rim adapted to engage and retainan external component. A cannula extends downward from a first side ofsaid base; and an adhesive layer is secured to the first side of thebase. The adhesive layer includes a second side with an adhesive. Asubstantially cylindrical port extends upward from a second side of saidbase. The port comprises a septum configured to have a fluid pathwaytherethrough. The fluid pathway is preferably formed by a slit extendingthough the septum, but alternatively the fluid pathway can be created bypuncturing the septum with a needle or other object. In a method ofusing an embodiment of the infusion set described herein, the basemember is prepared for adhesion to a patient's skin, and the needle andthe cannula are inserted through the patient's skin. The introducer capis disconnected and the needle is withdrawn from the base member. Theinfusion cap is then assembled on the base member such that the cannulaof the infusion cap is in fluid communication with the base cannula, andthe infusion cap is rotatable relative to the base member.

BRIEF DESCRIPTION OF DRAWINGS

Having thus summarized the general nature of the invention, certainpreferred embodiments and modifications thereof will become apparent tothose skilled in the art from the detailed description herein havingreference to the figures that follow, of which:

FIG. 1 is a perspective exploded view of an infusion set introducerassembly and base assembly having desired features and advantages.

FIG. 2 is a top view of the introducer cap of FIG. 1.

FIG. 3 is a cross-sectional view of the introducer cap of FIG. 1, takenthrough line 3-3.

FIG. 4 is a cross-sectional view of the introducer cap of FIG. 1, takenthrough line 4-4.

FIG. 5 is a perspective view of the base member of FIG. 1.

FIG. 6 is a cross-sectional view of the base member of FIG. 4.

FIG. 7 is a perspective view of an assembled introducer and base member.

FIG. 8 is a cross-sectional view of the assembly of FIG. 7 taken throughline 8-8.

FIG. 9 is a cross-sectional view of the assembly of FIG. 7 taken throughline 9-9.

FIG. 10 is a top view of an infusion cap having desired features andadvantages.

FIG. 11 is a cross-sectional view of the infusion cap of FIG. 10 takenthrough line 11-11.

FIG. 12 is a perspective view of an assembly of an infusion cap and abase member.

FIG. 13 is a cross-sectional view of the assembly of FIG. 12 takenthrough line 13-13.

FIG. 14 is a cross-sectional view of the assembly of FIG. 12 takenthrough line 14-14.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

An infusion set having desirable features and advantages will now bedescribed with reference to the attached figures. Although the followingdescription is provided in the context of an infusion set for use withan insulin pump, the skilled artisan will recognize that the features ofthe present infusion set can provide advantages in other applications aswell.

The infusion set illustrated in FIGS. 1-14 and described hereingenerally comprises a base assembly 20 adapted to removably receive anintroducer assembly 30 and an infusion assembly 40 (See FIG. 13).

FIG. 1 illustrates an exploded view of components of the base assembly20 and the introducer assembly 30. The base assembly 20 is generallyconfigured to be secured to a patient's skin by an adhesive layer 50 tomaintain a soft cannula 52 within a patient and to allow an infusion cap54 (see FIGS. 10-14) to be mounted to the base assembly 20 fordelivering a fluid through the cannula 52 and into a patient's body. Thebase assembly 20 preferably comprises a base member 60 with a softcannula 52 extending from a first side of the base member 60, a port 62extending from a second side of the base member 60, and an adhesivelayer 50 securable to the second side of the base member 60.

The introducer assembly 30 is generally configured to be removablyengageable with the base assembly 20 to facilitate introduction of thesoft cannula 52 through a patient's skin to a desired depth in thepatient's sub-dermal fatty tissue.

FIGS. 1-4 illustrate embodiments of an introducer assembly 30 comprisingan introducer cap 64 and an introducer needle 66 extending downward fromthe cap 64. In the illustrated embodiment, the introducer cap 64 isgenerally dome-shaped, and has a handle portion 72, a port-engagingportion 74, a base-engaging portion 76, and release grips 100.

As illustrated, the handle portion 72 generally includes a flange with aneedle-holding section 22 extending through a central portion of theflange 72. In one embodiment, the introducer cap 64 is formed with aneedle-holding section 22 comprising a lumen into which an introducerneedle 66 can be subsequently inserted and secured. Alternatively, theintroducer needle 66 can be molded into the material of the introducercap 64 by any of a variety of over-molding processes available to theskilled artisan. According to one embodiment, the needle-receivingsection 22 extends partially into the cavity 84 of the port-engagingportion 74 to provide additional length along which the needle 66 willbe supported. The supported length of the needle (i.e. the length of theneedle held within the needle-holding lumen 22) can vary as needed forneedles of various lengths. For example, in the case of a needle with anoverall length of about 1″, a needle-receiving section preferably has alength of between about 3/16″ and about 5/16″.

Introducer needles can be provided in a variety of sizes as needed for aparticular cannula or application. For example, needles can be providedwith lengths from about 0.5″ to about 2″ or more. In further alternativeembodiments, needles outside of these ranges can also be used as needed.Additionally, an introducer needle can be solid, or may have a hollowinner lumen as desired.

The handle section 72 of the introducer cap 64 is illustrated ascomprising a substantially planar section extending upward from thedome-shaped cap 64. The handle section 72 preferably has a substantiallylarge surface area such that a patient or caregiver can easily grasp theintroducer cap 64 for assembly with the base member 60 and for insertionof the needle 66 into the patient. For example, as shown, the handlesection can extend across a substantial portion of the diameter of theintroducer cap. The handle section 72 can also extend upwards from thedome of the cap by about 0.2″ to about 1″. In one preferred embodiment,the handle section 72 extends about ½″ above the top of the introducercap 64. The skilled artisan will recognize that the handle portion 72can be otherwise shaped and sized as desired. Alternatively, theintroducer cap 30 can be held by the release grips 100 or any otherconvenient portion during insertion of the needle as will be furtherdescribed below.

As illustrated in FIG. 2, the port-engaging portion 74 preferablycomprises a cylindrical section configured to closely surround the port62 of the base portion 60 in an assembled position. The tubular wall 86of the port-engaging portion 74 is generally configured to contact thetop surface 92 of the base member 60 as will be further described below.A close fit between the port 62 and the tubular wall 86 of theport-engaging portion 74 of the introducer cap 64 advantageouslyprovides a minimum of movement of the base member 60 relative to theintroducer cap 64 during introduction of the needle 66 and catheter 52into a patient.

In the illustrated embodiment, the base-engaging portion 76 of theintroducer cap 64 generally comprises a pair of wings 98 extendingdownward from the cap. The wings 98 preferably include barbed feet 94adapted to engage a rim 96 of the base member 60 (FIG. 6). The barbedfeet 94 are generally configured to secure the introducer cap to thebase member disc 60. The height ‘h’ between the top of the barbed feet94 and the bottom of the tubular wall 86 of the port-engaging portion 74is generally selected to correspond to dimensions of the base member 60in order to provide a secure fit between the assemblies 20 and 30 aswill be further described below. In an alternative embodiment, thebarbed feet 94 can be omitted, and the introducer cap can be held in anoperative position relative to the base assembly 20 by other means. Forexample, the port 62 and the port-engaging portion 74 can alternativelybe threaded such that the introducer cap can screw onto the base member.

In the illustrated embodiment, the introducer cap 64 is generallycircular as viewed from above (see FIG. 2). As shown in FIG. 2, a pairof release grips 100 are provided on opposite sides of the circular cap64 in the area of the barbed fee 94 so as to allow the introducer cap 64to be released from engagement with the base member by the applicationof a force at the arrows 102, preferably by pinching the release grips100 between the thumb and middle finger. In the embodiments illustratedin FIGS. 2-4 and 8, the release grips 100 comprise vertically extendingportions which can be integrally formed with the dome-shaped portion ofthe introducer cap 64. Alternatively, the vertically extending portionscan be separate sections which can be made separately from theintroducer cap and secured thereto by any appropriate method. Inoperation, application of a force at the arrows 102 will create abending moment at the intersection of the vertically extending portionand the done-shaped cap. This bending moment will cause the wingsections 98 of the introducer cap 64 to bend radially outwards, therebyreleasing the barbed feet 94 from engagement with the base member 60.

In alternative embodiments, the release grips 100 can include convexprotrusions, concave recesses, or other shapes to allow the shape of theintroducer cap to be deformed in order to facilitate removal of theintroducer cap 64 from the base member 60. The illustrated release grips100 advantageously allow the user to grasp the introducer cap 30 withhis or her fingers without simultaneously grasping the rim 96 of thebase member 60, making it easier to release the introducer cap 64 fromthe base member 60. Alternatively, a separate tool can also be used togrip an introducer cap 64 and/or an infusion cap 54 during assembly ordisassembly of a cap with the base member 60.

The introducer cap 64 is preferably injection molded from a plasticmaterial suitable for use in medical applications. In one embodiment,the introducer cap 64 is made of a biocompatible ABS, and has a wallthickness ‘t’ of about 0.030″+/−0.005″. In alternative embodiments, theintroducer cap 64 can be made of other biocompatible materials such aspolycarbonate in any appropriate size as desired.

As shown in FIG. 3, the introducer cap 64 can also include ribs 104extending radially from the tubular wall 86 of the port-engaging portion74. Ribs 104 can be provided in any size and number as desired in orderto provide additional rigidity to the joint between the tubular wall andthe body of the introducer cap.

Embodiments of the base assembly 20 will now be described with referenceto FIGS. 1, 5 and 6. In the illustrated embodiments, the base assembly20 comprises a base member 60 with a port 62 extending upward therefromand a soft cannula 52 extending downward from the disc 60. In theillustrated embodiments, the base member 60 is shown as being asubstantially circular disc; however, in alternative embodiments, thedisc can have other shapes such as an ellipse, polygon, etc. A circularbase member 60 as shown provides the advantage of allowing an introducercap 64 and/or an infusion cap 54 attached thereto to be rotatable aboutthe central axis of the base member 60.

The illustrated base member 60 comprises a rim 96 surrounding thedisc-shaped base member 60. The rim 96 is generally configured toreceive the barbed feet of an introducer cap 64 and/or an infusion cap54 to retain the cap member (64 or 54) on the base member 60. As seen inFIG. 6, the rim 96 of the base member 60 can include a notched portion110 to provide clearance for the barbed feet 94. The rim 96 can also beprovided with a sloped edge 112 for facilitating assembly of the capmembers 54 and 64 with the base member 60 as the cap is pressed axiallydownward onto the base member 60 as will be further described below.

With particular reference to FIG. 6, one embodiment of the base member60 is adapted to have a substantially low profile. For example, in someembodiment, the overall height, ‘q’ can be between about 0.15″ and about0.25″. In one preferred embodiment, the overall height ‘q’ of the basemember 60 is about 0.20″.

According to one embodiment, the distance ‘d’ between the bottom surfaceof the rim 96 and the top surface 92 of the base member 60 is selectedto correspond to the height ‘h’ between the top edge of the barbed feet94 and the bottom edge of the tubular wall 86 of the port-engagingportion of the introducer cap 64 (as discussed above with reference toFIG. 3) and the infusion cap 54 (as further discussed below withreference to FIG. 11). In one embodiment, the dimensions ‘d’ and ‘h’ aresubstantially the same, thereby providing a substantially rigidconnection between a cap (64 or 54) and the base member 60.Alternatively, the dimension ‘h’ can be made larger than the dimension‘d’ in order to provide a looser connection between a cap (64 or 54) andthe base member 60.

Certain advantages arise from loose or tight connections between thebase member 60 and a cap member (64 or 54). For example, a tightconnection between the base member 60 and the introducer cap 64 willassist in control of the needle 66 during insertion of the needle 66 andthe soft cannula 52 through the patient's skin. On the other hand, aloose but secure connection between the base member and the infusion cap54 will allow the infusion cap 54 to rotate and move about the basemember without transmitting substantial torsional stress to the basemember 60 and the patient.

As illustrated in FIG. 6, the base member 60 comprises a fluid pathwayextending from the top 114 of the port 62 through the soft cannula 52extending from the bottom surface 118 of the base member 60. The centralportion of the fluid pathway preferably comprises a substantiallyfunnel-shaped section 120 with a tubular lower section 122. According toone embodiment, a funnel-shaped insert 124 can be provided to line theinterior surface of the funnel-shaped section 120. The insert 124 ispreferably made of a rigid material, such as a metal, to protect thewall of the funnel-shaped section 120 during insertion of the introducerneedle 66 (FIGS. 1 and 3). The insert 124 prevents the wall of thefunnel-shaped section 120 from scoring and/or causing fragments of thewall to break away and enter the infusion stream.

The soft cannula 52 extending from the base member 60 can comprise anymaterial recognized as being suitable for use in fluid-carrying lumensimplantable within a patient's body. Infusion sets can be offered withsoft cannulas having a variety of lengths to accommodate differences inthe desired depth to which the cannula extends within a patient. As willbe understood by the skilled artisan, in many embodiments the softcannula 52 preferably extends into a subcutaneous fat layer of apatient. Thus, cannulas of various lengths are helpful in allowing avariety of different patients with more or less subcutaneous fat to usethe present infusion set. For example, soft cannulas can be produced inlengths from about ¼″ to about 2″. Depending upon the intended use, softcannulas with lengths outside of this range may also be employed.

FIGS. 1, 5 and 6 illustrate embodiments in which the cannula 52 extendsfrom the bottom surface 118 of the base member 60 at a substantiallyright angle. In alternative embodiments, the cannula 52 can beconfigured to extend from the base member at an angle substantially lessthan 90°.

In alternative embodiments, the soft cannula 52 could be replaced by asubstantially hard cannula or hypodermic needle as may be desired. Sucha hard cannula or needle could also be provided at any angle relative tothe bottom surface 118 of the base member 60 as desired.

In one embodiment, the soft cannula 52 can be secured to thefunnel-shaped insert 124, and the cannula-funnel assembly can beinserted into the funnel-shaped section 120 of the base member 60. In analternative embodiment, the soft cannula 52 can be secured directly tothe base member to extend from the bottom surface 118 of the base member60 at an inner or outer surface of the tubular lower section 122 of thefunnel-shaped portion as desired.

As shown in FIGS. 1, 5 and 6, the port 62 extending from the base member60 preferably comprises a self-sealing septum 130 positioned in thecavity 132 above the funnel-shaped section 120 of the port 62. Theseptum 130 is preferably positioned at or near the top of the port 62 soas to present a readily accessible surface for swabbing with antisepticto maintain the septum 130 free of bacteria and other debris. Thepositioning of the septum above the funnel-shaped section 120 helpsmaintain the funnel-shaped section 120 sterile. In the illustratedembodiment, the septum 130 preferably comprises a slit 134 forming afluid pathway through the septum 130. Although the illustrated slit 134is in the shape of a straight line, in alternative embodiments, the slit134 can be circular, cross-shaped, or otherwise shaped to provide asealable fluid pathway through the septum 130. In further alternativeembodiments, a pre-formed slit 134 can be omitted, and the septum 130can be punctured with a needle or other sharp object to create a fluidpathway through the septum 130.

In order to create a self-sealing fluid pathway, the septum 130 isgenerally made of a substantially resilient material biased toward asealed position. In one embodiment, the septum 130 is made of a moldeddisc of silicon, polyurethane or other appropriate material which can besecured to the port 62. The securing of the septum 130 to the port 62can be accomplished by any suitable adhesive, bonding or othersecurement process such as heat sealing, sonic welding, etc. Inalternative embodiments a suitably resilient material such as silicone,polyurethane, or other suitable elastomeric material can be molded intothe cavity 132 at the top of the port 62 (see FIG. 6). In still furtherembodiments, the septum 130 can be replaced by any of a variety ofmechanical check-valves or other seals configured to provide are-sealable fluid pathway. In another embodiment, the septum 130 and thebody of the base member 60 can both be integrally formed from the samesubstantially resilient material.

According to one embodiment, as illustrated for example in FIG. 8, theseptum 130 is a molded disc of a substantially resilient material thatis retained in the port 62 by heat staking. As shown, a portion of aport wall 136 is provided that extends above the septum 130 andsurrounds the cavity 132 in which the septum 130 is located. The portwall 136 is heat staked by slightly heating the material of the wall 136to a temperature below its melting temperature, but sufficiently high tosoften the material of the wall. Once the port wall 136 material hasbeen softened, it can be deformed radially inward slightly so as to trapthe septum 130 in the cavity 132 of the port 62. The heat stakingprocedure can be performed uniformly around the circumference of theport, or at intervals around the wall 136. The skilled artisan willrecognize that alternative methods can also be used for securing theseptum within the cavity 132, such as bonding, welding, etc as describedabove.

As shown in FIG. 6, the tubular lower portion 122 of the funnel-shapedsection 120 is surrounded by an annular space 138 configured to allow aneedle guard 140 to be affixed to the funnel-shaped section 120 (seeFIGS. 8 and 9). In the embodiments illustrated in FIGS. 7 and 8, theneedle guard 140 comprises a section of tubing of sufficient length andrigidity that the guard 140 will not expose the sharpened needle tip.The needle guard 140 can comprise any suitable material and/or design asdesired. For example, in one embodiment, the needle guard 140 comprisesa section of vinyl tubing which extends 144 about ⅛″ to about ½″ beyondthe needle tip in the assembled position shown in FIG. 8. In alternativeembodiments, the annular space 138 can be omitted and the needle guard140 can be retained over the needle 66 by some other means, such as by atighter friction-fit around the needle 66 or by providing a needle guardas part of the packaging for the infusion assembly. In some embodiments,as illustrated in FIGS. 3 and 4, the needle guard 140 can be configuredto be attached directly to the introducer cap 64 in order to extend atleast a distance 146 of between about 1/16″ and about ⅛″ or more beyondthe needle tip. In an alternative embodiment, a needle guard can beprovided to attach to the barbed feet 94 of the introducer cap 64 afterthe introducer cap 64 has been removed from the base member 60.

If desired, the annular space 138 of the base member 60 can be providedwith annular rings 142 to aid in release of the base member from a moldhalf during an injection molding process. As will be clear to theskilled artisan, it is often desirable that an injection molded partremain temporarily retained in one of the halves of an injection molduntil the mold half is moved to a location over a drop bucket, at whichtime the part can be ejected from the mold by ejector pins. In theabsence of the annular rings 142, an injection molded base member 60 mayprematurely fall out of the mold. It should be noted that the basemember 60 need not be made by injection molding, and could be made byany number of other suitable processes in which case, the annular rings142 might be excluded.

According to one embodiment, an adhesive layer 50 such as thatillustrated in FIG. 1 can be secured to the bottom surface of the basemember 60. The adhesive layer 50 is generally configured to allow thebase member 60 to adhere to a patient's skin as will be furtherdescribed below. The adhesive layer 50 is typically provided with abacking layer 150 to protect the adhesive side 152 of the adhesive layer50 from dirt, dust and other contaminants that may reduce the ability ofthe adhesive side 152 to securely adhere to a patient's skin and mayincrease the risk of infection at the injection site. The adhesive layer50 can be secured to the bottom surface 118 of the base member 60 by anysuitable bonding substance or process. For example, the adhesive layercan be adhered to the base member with a glue or other bonding agent.Alternatively the adhesive layer 50 can be bonded to the base member 60by heat sealing, sonic welding, or any other suitable process.Alternatively, the function of adhering the base member 60 to apatient's skin may be accomplished by other means known to those ofskill in the art.

FIGS. 7-9 illustrate one embodiment of an introducer assembly 30attached to a base assembly 20. As shown, the introducer cap 64 ispreferably attached to the base member 60 by the engagement of thebarbed feet 94 with the rim 96 of the base member 60. By removablyengaging the introducer cap to the base member 60, the needle 66 istemporarily secured within the cannula 52 to provide a rigid puncturingsurface during the process of inserting the cannula 52 into thepatient's body. If the introducer cap 64 or needle 66 were not engagedwith the base member 60, then the introducer cap 64 and base member 60could separate or become misaligned during insertion into the patient,possibly entailing repeated puncturing, and causing unnecessary pain anddiscomfort to the patient. In the illustrated embodiment, the engagementof the introducer cap 64 and the base member 60 allow these componentsto be pressed together against the patient, preferably with a single,rapid motion. The cylindrical wall 86 of the port-engaging portion 74also preferably engages the upper surface 92 of the base member 60.

The port-engaging portion 74 of the introducer cap 64 is preferablyadapted to surround the port 62 of the base member 60. This provides fora close fit between the introducer cap 64 and the base member. Thisclose fit can aid in preventing the base member from rocking orperforming other unwanted movement relative to the introducer cap 64.These same advantages can also be beneficial in the context of theinfusion cap 54 as will be further described below. In one embodiment,the inner diameter of the port-engaging portion 74 is about 0.025″ toabout 0.1″ larger than the port 62 of the base member 60. Depending uponthe desired application, in alternative embodiments, the inner diametermay be outside of this range.

With reference to FIGS. 10-14, embodiments of infusion assemblies 40adapted to be mounted to the base member 60 will now be described. Asillustrated, an infusion cap 54 can be configured to attach to a basemember 60 in a similar manner to that of the introducer caps 64discussed above.

With reference to FIG. 11, one embodiment of the infusion cap 54 isadapted to have a substantially low profile. For example, in someembodiment, the overall height, ‘s’ can be between about 0.300″ andabout 0.400″. In one preferred embodiment, the overall height ‘s’ of theinfusion cap 54 is about 0.335″.

In one embodiment, an infusion cap 54 comprises a tube-receiving lumen160. The tube-receiving lumen 160 is generally configured to accept asection of flexible tubing 162 with an internal lumen 164 as shown inFIG. 11. The tube-receiving lumen 160 can comprise any appropriatetransverse cross-section (e.g. as viewed in the axial direction) asdesired, but will typically have an axial cross-section corresponding toan axial cross-section of the selected tube 162.

The tube 162 typically comprises a circular cross-section with adiameter of between about 0.030″ and about 0.10″. The tube can be anymaterial suitable for use in transmitting fluids in medicalapplications. Typically the tube will be made of polyethylene or medicalgrade polyvinyl chloride, although other materials can alternatively beused. The end of the tube 162 that is opposite from the infusion cap canbe provided with a connector for joining the tube in fluid communicationwith the output of a pump or other fluid source. For example, in oneembodiment, the opposite end of the tube 162 comprises a Luer lockconnector. Other connectors can alternatively be used as will beunderstood by the skilled artisan in view of the present disclosure.

The tube 162 can be secured to the infusion cap 54 by any suitableprocess or mechanism as desired. For example, in the illustratedembodiment, the tube-receiving lumen 160 tapers in diameter from theouter end 166 to the inner end 168. This taper provides for a tightpress-fit, allowing the tube to be retained by friction between theinner wall of the tube-receiving lumen 160 and the outer wall of thetube 162. If desired, the tube 162 can be further secured in thetube-receiving lumen by adhesives, sonic welding, heat sealing, or anyother suitable process.

As can be seen in FIGS. 11, 13 and 14, the infusion cap 54 can furthercomprise a hard cannula 170 with a lumen 172 configured to be in fluidcommunication with the tube 162. The hard cannula 170 can be integrallymolded as part of the infusion cap 54, or it can be subsequentlyattached by any suitable process. The inner diameter of the hard cannulalumen 172 will typically be selected to allow a sufficient fluid flowrate therethrough. For example, in some embodiments, the lumen 172 hasan internal diameter of between about 0.01″ and about 0.03″, and in oneembodiment, the lumen 172 has an internal diameter of about 0.02″. Otherdiameters outside of these ranges can alternatively be used as desired.

In the embodiment of FIG. 9, the hard cannula 170 is surrounded by acylindrical wall 86 to protect the cannula 170 from contact with auser's fingers, or other objects that might contaminate the sterility ofthe lumen. The hard cannula 170 can be positioned within the cylindricalwall 86 such that the cannula is substantially co-axial with thecylinder wall 86, thereby providing for automatic alignment of thecannula with the exact center of the septum 130 as the cylinder wall 86engages the port 62. As described with reference to the introducer cap64 above, the cylindrical wall 86 of the infusion cap 54 is preferablysized and configured to provide a substantially close fit with the port62 of the base member 60. Providing a close fit advantageously assistsin alignment of the hard cannula 170 with the port. The close fit alsoadvantageously causes any forces applied to the infusion cap 54, such asthe cap being bumped or the tube 162 being pulled, will be applied atthe intersection of the port and the port-engaging portion 74 ratherthan at the barbed feet (which could cause the infusion cap to becomedisconnected from the base member 60).

The hard cannula 170 is generally configured to extend through at leasta portion of the septum 130 when the infusion cap 54 and base member 60are assembled. Thus, the hard cannula 170 is typically dimensioned suchthat it extends into the port-engaging portion 74 a sufficient distancethat when the wall of the port-engaging portion contacts the top surface92 of the base member 60, the hard cannula 170 will extend through atleast a portion of the septum 130. Thus, the dimension ‘e’ between theoutlet 174 of the hard cannula 170 and the bottom edge 182 of theport-engaging portion 74 is preferably less than the dimension ‘j’between the top surface 92 of the base member and the bottom of thecavity 132 in the port 62 (see FIG. 5). In alternative embodiments, thedimension ‘e’ can be equal to or greater than the dimension ‘j’ if it isdesirable that the hard cannula 170 extend only partially through theseptum 130, for example. In one preferred embodiment, as illustrated inFIG. 11, the hard cannula 170 extends completely through the septum 130.

The hard cannula 170 also preferably has sufficient column strength tobe inserted through the septum 130 (or other sealing member). Thus, thehard cannula 170 is typically made of a rigid material such as PVC, PET,nylon, stainless steel, or other material suitable for use in medicalapplications and having sufficient rigidity.

Similarly to the introducer cap 64, the infusion cap 54 also preferablycomprises release grips 100 which can be compressed to release the capfrom engagement with the base member 60. In the embodiment illustratedin FIG. 10, the release grips 100 are shown as scalloped convex segmentslocated at about 90° to the wings 98 and barbed feet 94. The releasegrips 100 can be engaged by a user's fingers to release the cap 54 or 64from engagement with the base member 60. By pinching the release grips100, the circular shape of the cap 64 is deformed into an ellipticalshape with the barbed feet 94 along the major axis of the ellipse. Thus,pinching the cap 64 at the release grips 100 causes the barbed feet tomove radially outwards and away from the edges of the base member 60,thereby releasing the cap 64 from the base member 60. In alternativeembodiments, the release grips 100 of the introducer cap 64 and/or therelease grips 100 of the infusion cap 54 can comprise smooth convexsections, concave sections, or any of a variety of other shapes.

Methods of using the infusion set embodiments described above will nowbe described with continued reference to FIGS. 1-11. In preparation forintroduction of the infusion set into a patient, the base assembly 20and the introducer assembly 30 will typically be assembled as shown inFIGS. 6 and 7. In some embodiments, the base assembly 20 and theintroducer assembly 30 can be provided to an end user in a pre-assembledcondition. Alternatively, in other embodiments, the parts can beprovided separately for assembly by an end user.

According to one embodiment, a patient will follow these steps in orderto introduce the soft cannula 52 and connect the infusion set. Thepatient can remove the needle guard 140 from the position shown in FIG.7 by gripping the needle guard 140 and pulling it axially away from theintroducer cap 64, thereby exposing the introducer needle 66 and thesoft cannula 52 extending from the underside 118 of the base member 60.

The backing layer 150 can then be removed from the adhesive layer 50,thereby exposing the “sticky” side of the adhesive layer to be adheredto the patient's skin. While gripping the introducer cap 64 in anydesirable manner, or using any suitable tool, the introducer needle 66and soft cannula 52 are rapidly pressed against and inserted through thepatient's skin and into the patient's sub-dermal tissue until theadhesive layer 50 contacts the patient's skin and adheres thereto. Theadhesive layer 50 is preferably substantially free from folds or‘bubbles,’ thereby forming a close, secure attachment.

Once the needle 66 and soft cannula 52 have been inserted to the desireddepth, the introducer cap 64 can be removed from the base member 60 andfrom the patient. In order to remove the introducer cap 64 from the basemember 60, the release grips 100 can be engaged by a user's fingers andcompressed, thereby deforming the circular cap and causing the barbedfeet 94 to be released from engagement with the rim 96 of the basemember 60. In alternative embodiments, the release grips 100 can becompressed by a supplemental tool. In further alternative embodiments,the introducer cap 64 can be configured such that release grips areotherwise manipulated (e.g. twisted, spread apart, etc) in order toremove the introducer cap 64 from the base member. In still furtherembodiments, the barbed feet 94 may be omitted, as discussed above, orreplaced with a suitable alternative structure, thereby allowing a userto merely pull outward on the introducer cap 64 to remove the needle 66.

Once the introducer cap 64 is disengaged from the base member 60, thecap is pulled outward and away from the patient, and the needle 66 iswithdrawn from the soft cannula 52. The soft cannula remains within thepatient, extending to a desired depth within the patient's sub-dermaltissue and held in place by the base member 60 and the adhesive layer50. As described above, the septum 130 is generally configured to sealthe fluid pathway upon removal of the needle 66, thereby preventingunwanted flow of fluids or contaminants through the cannula 52.

Once the base member 60 and cannula 52 are in place, the infusion cap 54can be joined to the base member 60, thereby placing the tube lumen 164of the infusion tube 162 in fluid communication with the soft cannula52. As the user assembles the infusion cap 54 with the base member 60,the port-engaging portion 74 will surround the port 62, thereby aligningthe hard cannula 170 of the infusion cap 54 with the slit 134 in theseptum 130. As mentioned previously, the slit can be pre-formed, or ahole can be formed by the needle 66 extending through the septum 130.The automatic alignment of the hard cannula with the septum slit 134allows for simple assembly and diminished risk of misalignment. This isparticularly advantageous to diabetic patients who often havedeteriorating eyesight.

The infusion cap 54 can be pressed against the base member until thebarbed feet 94 “snap” into engagement with the rim 96 of the basemember. In one embodiment, the infusion cap 54 can be configured tocreate an audible “snap” sound when it is pressed onto the base member60 to enable a user to audibly and/or tactilely verify the completeengagement of the infusion cap 54 on the base member 60.

There are many circumstances, such as when the patient bathes, sleeps,plays sports, etc, when it is desirable to disconnect the infusion setwithout removing the cannula from the patient's body. When the infusionset is disconnected, the base member is exposed to potentialcontamination by dust, dirt, bacteria and other contaminants. Inaddition, the possibility of the base member becoming snagged or pulledby clothing or other objects poses potential problems. As will be clearto the skilled artisan in view of the present disclosure, these issuesand others are addressed by the advantageous features of the infusionset embodiments shown and described herein.

The illustrated infusion set provides for repeated disconnection andreconnection of the infusion cap 54 to and from the base member 60. Theinfusion cap 54 can be removed from the base member 60 by engaging andapplying a force to the release grips 100 in order to cause the barbedfeet 94 to disengage from the rim 96 of the base member 60. Similarly tothe introducer cap 64, the infusion cap 54 can be engaged by a user'sfingers or any other appropriate tool or device to facilitate removal ofthe cap from the base member 60.

The infusion set embodiments described herein provide a single fluidpathway through the base member by allowing the hard cannula 170 of theinfusion cap 54 to extend through the same path through the base memberas the needle 66 of the introducer cap 64. This arrangementadvantageously reduces the number of possible points of contaminationwithin the infusion system. When the infusion cap 54 is removed, theseptum 130 will seal the fluid pathway to prevent the unwanted egress ofblood, and to prevent particles and unwanted fluids from entering thepatient through the cannula 52.

As mentioned above, the base member 60 and cannula 52 can be left inplace within a patient for a few days or longer, and in somecircumstances, the base member may be left disconnected from theinfusion cap for a period of a few hours or more. The illustrated basemember 60 has an advantageously low profile, thereby reducing thelikelihood of the base member 60 becoming “snagged” on clothing, towels,or other objects when the patient bathes, dresses, etc. The dome-shapedinfusion cap of the above embodiments also advantageously covers theentire base member, thereby protecting the base member fromcontamination by dirt, dust, germs, or other contaminants. The lowprofile of the base member 60 and the substantially flat top surface ofthe septum 130 are also advantageously substantially free from cavitiesor crevices which might hold contaminants. In addition, the low-profiledesign diminishes the likelihood that a patient will inadvertently bumpor jostle the infusion set during use, causing discomfort and/orrequiring repositioning or replacement of the infusion set.

Additionally, the position of the septum 130 at a distal surface of thebase member relative to the patient's body advantageously provides forsimplified cleaning of the septum. As shown and described above, theseptum 130 is preferably positioned such that it is flush with the topedge of the port 62. This provides for easy cleaning of the septum 130and the port 62, such as with a cotton swab and alcohol, or any othercleaning products suitable for use in medical applications.

In other circumstances, it is desirable for the infusion set to havesubstantial freedom of movement while installed and assembled. Forexample, once assembled, the embodiment of an infusion set illustratedin FIG. 12 has the advantage that the infusion cap 54 can rotaterelative to the base member about an axis perpendicular to the plane ofthe bottom surface 118 of the base member and extending through thecenter of the port 62. Such rotatability advantageously allows a patientto move the tube 162 to the front or the back of the patient's bodywithout inducing a twisting moment on the base member 60. Thus, aninfusion set having an infusion cap that is capable of rotation about acentral axis of a base member while maintaining fluid communicationbetween a pump and a patient's body has the distinct advantage ofproviding the patient with substantial freedom to position the infusiontube 162 at any radial position relative to the base member.

The end of the tube 162 that is opposite the infusion cap can beconnected to a suitable pump or other fluid source either before ofafter assembly of the infusion cap 54 and base member 60. In alternativeembodiments, an infusion system may comprise additional tubes,connectors, or other components between the soft cannula and a fluidsource.

In alternative embodiments, the base member 60 shown and describedherein can be employed to deliver medicants or other therapeutic fluidsto a patient without the use of the other members of the infusion setdescribed herein. For example, a base member such as those describedabove could be used in combination with a standard hypodermic syringe todeliver a therapeutic fluid to a patient by extending a cannula of thesyringe through the septum and injecting the fluid through the softcannula of the base member and into the patient.

Although certain embodiments and examples have been described herein, itwill be understood by those skilled in the art that many aspects of themethods and devices shown and described in the present disclosure may bedifferently combined and/or modified to form still further embodiments.For example, any one component of the infusion sets shown and describedabove can be used alone or with other components without departing fromthe spirit of the present invention. Additionally, it will be recognizedthat the methods described herein may be practiced in differentsequences, and/or with additional devices as desired. Such alternativeembodiments and/or uses of the methods and devices described above andobvious modifications and equivalents thereof are intended to beincluded within the scope of the present invention. Thus, it is intendedthat the scope of the present invention should not be limited by theparticular embodiments described above, but should be determined only bya fair reading of the claims that follow.

1. A base for an infusion set, the base comprising: upper and lowersides; a base cannula extending downwardly from the lower side; a portextending upwardly from the upper side, the port being in fluidcommunication with the base cannula, the port comprising a septumadapted to seal said port from fluid communication therethrough; afunnel-shaped section disposed within the port and in fluidcommunication with the base cannula, a funnel-shaped insert disposedwithin the funnel-shaped section and adapted to protect the surface ofthe funnel-shaped section from scoring.